Motor for gathering reels



June' 30, 1925.

E. ASHWORTH MOTOR FOR GATHERlNG REELS Filed July 1:5, 192?,

ffy, 5

sv "M7/ ATTORNEY SWRWLA Patented June 30, 1925.

` UNITED STATES glUiTEN'r*v OFFICE.

EVERETT Asxworvrmor NEW Yonx. N. Y.,AssIGNoR `'ro WEs'rINoHoUsE IELECTRIC f & MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA. f

Moron. ron GATHERING nEELs.

Application med July 1s, 192s. lserial No. 651,210.

To all 'whom it may concern: v Be it known that I, Evnnm'rfAsHwon'rH, av citizen ofy the United States, and a resident of New York, in the county of Bronx and State of New York, have invented a new and useful Im rovement in Motors for Gathering Reels, o which the following 1s a specification.

"My invention relates to gathering reels andl has 'speciali' reference yto ,electrically driven 'gathering reels, for mining locomo-l tives. n

It 'is often `necessary to operate mining locomotives over which no trolley wire has l5 beenextended. yFor this purpose a conductory cable is rovided and wound over a motor-operate drum" mounted upon the locomotive. By connecting the cable terminal to a trolley wire,l or other supply line,

the operation of the Ocomotive is made independentof the trolley wire and is limited only by the length of the cable wound upon the drum. Durlng rsuch operation, it is 1m' portant that no loose cable shall lie u n the track, liable to be damaged by the w eels of the -lomotive or otherwise: To this end means-'are provided whereby the cable is always kept gathered on the' reel, independ-v ently of the movementfof the locomotive.

In U. S. Patent 1,206,309, ranted November28, 1916tovJoseph 'Le Y te Davis and assigned to the `Westinghouse.Electric and Manufacturing Com any is shown an electric motor designed or Operatin a'gathering reel, andthe desired torque c aracteristic of such a motor is stated. The aboveg menticnedmotor was well adapted to meet uirements of mining locomotives for, limite `speed service. Itis particularly-im-y portant, however,`that when the reel is gathering inthe cable,`that is, when the locomo` tive is advancing, .'suicient torque vshall be provided to keep: the cable taut and to previent. the wheelsafrom ing `over the cable,

which=obtain in modernlocomotive operation andfwhich are substantially in excess of the speed of the olderlocombtifves.

Accordingly, the general object of my invention lis to provide an-improved ymotor ,y which isl capable -of' deliveringL a"substan tially uniform gathering torque during'the notwithstanding theihigh operating speedsy entire speed-range of advancing of modern locomotives. I achieve thisgobject by providing, in addition to the shunt field winding used VVon the motor of the old type', a series field winding in bucking relation yto the shunt field winding. f'

The novel features of my invention will be best understoodby reference to the accompanying drawings, lwherein p v Figure 1 is a diagrammatic view showing the electrical connections of a mining locomotive equipped with a 'motor-Operated gathering reel. y

Fig. 2 1s a simlarview showing the motor for operating the gathering reel of Fig. 1 and embodying my invention.

Fig. 3 is an explanatory curve referred vto hereinafter. y

Referring to 1, the main driving motor or motors lof a locomotive'are arranged to be supplied, by means of a circuit 2, from a trolleyl wire 3 and va. return conductor 4 of a direct-current source (not shown). By means of a switch 5, the supply wire 2 may be' connected to a trolley 6 for ordinary operation or to a conductor cable 7 for operation over parts of the tracks which are not provided with a trolley wire. The conductorcable is woundu on afreelor drum 8 and has a hook-terminal 9 for connection with the trolley wire.

The reel ordrum 8 is operated by a mo tor illustratedin Fig. 2 and built into the drum. `The motor comprises a direct-current armature 1l, a seriesr field Winding 13 anda shuntl field winding 12 'arranged to be bucked by the series field winding. The mainmotor circuit comprising the armature ll'and the series lfield winding 13 has terminal'conductors 14 and 15,' respectively. The shunt yfield winding 12 is connected at one end to the terminal conductor 14 and is provided at the other end with an' additional terminal conductor 16. The terminall con# ductor 14 is directly connected to the return conductor 4, and therv terminal conductorl is connected to the cable 7 and one of ythe, stationary vcontact points 17 of the switch 5 through an internal resistor or resistor-sectiony 18, which is individual to thearmature circuit, and an externalv resistor or resistorsection 19, which is traversed by the total current flowing through both the armature 11 and the shunt field Winding 1Q, the shuntfield terminal conductor 16 being connected between the resistors 18 and 19. In the preferred embodiments of my invention, the external resistor portion 19 is larger than the internal resistor portion 18, thus causing the total current supplied to the motor to be relatively constant, considering the Wide speed range.

The operating characteristics of the motor and their desirabilityv in reeling service will be best understood and recognized from the curves in Fig. 3. Dotted-line curve 20 re resents the torque at the armature sha t, as a function of the locomotive speed, for a motor constructed according to above mentioned Patent 1,206,309. Full-line curve 21 illustrates the torque of a motor embodying my invention. The torque curve ot' the oldtype motor shows a hump extending over a. relatively small speed rz nge. This range of maximum torque may be shifted to a limited extent by proper choice of the resistors 18 and 19, but it has been found that, with a motor of given size, a satisfactory gathering torque is not obtainable at locomotive speeds exceeding four miles per hour.

Through the use of a motor constructed according to my invention, the above inentioned hump is extended over a Wider range of speeds in the advancing direction, so that the motor torque is maintained substantially constant during the entire gathering or reelingsin period. The apparent disadvantage of rapidly falling torque When paying out the cable is oi no harmful consequences, by reason of the fact that the frictiontorque will in most cases be sufficient to keep the cable taut during such period.

The improved torque characteristic is obtained through the balancing of the armature current and exciting field effected by the bucking series field Winding. At standstill, the motor has a certain definite torque which is a product of the armature current and the resultant field ofi' the two windings 12 and 13 acting in opposition to each other. lVith the locomotive advancing, the reel gathers in and the motor turns in the direction ot' its torque; a counter electromotive force is set up in the armature, reducing the armature current, but also reducing the bucking effect of the series field Winding. T he change of the armature current is thus y brought in inverse relation to the increase in thc field strength, and the torque is maintained at a substantially constant value.

My invention is not restricted to the particular use in mining locomotives as described above. It is equally applicable in traction-rope reels, haulage reels and generally in all applications requiring a torque motor of a similar character.

It is further obvious that various details ot construction described above may be changed without departing from the spirit ot my invention, I desire, therefore, that only such limitations shall be imposed there on as are indi 'ated in the appended claims.

I claim as my invention:

1. A motor for a gathering reel colnprising an armature, a series field winding and a resistor connectedin series relation across a source of electric energy, and a second field winding acting in opposition to said series field winding and connected in parallel re lation to the part of the circuit comprising said armature and a predetermined portion ot said resistor.

In combination with a direct-current motor associated mechanically with a movable body, ot a load turning the motor armature against its torque during one part of the movement and being operated by said armature during another part of the movement, said motor comprising au armature, a field Winding and a resistor connected in series relation and a second field winding connected in shunt relation to the portion of the circuit comprising said armature, series field winding and a portion of said resistor, said series field winding being arranged to buck the action of said shunt field winding.

3. In an electric vehicle a supply cable connected to a source of electrical energy, a gathering reel for said cable, an electric motor actuating said reel and adapted to exercise an approximately constant torque upon said cable while reeling in, and a torque decreasing with the speed of unreeling while paying out said cable, said motor comprising an armature, a bucking field winding and a resistor connected in series to said source of energy, and a main field winding connected in shunt to the portion of the circuit oomposed of the armature, the bucking field Winding and a part of said resistor.

4. The combination with a cable and a gathering reel therefor, of an electric motor for continuously exerting a unidirectional torque upon said reel and having au armature upon which a predetermined loadvarying voltage is impressed, a shunt field winding upon which a differing voltage is impressed, and a bucking series field winding in series relation to said armature.

5. The combination with a cable and a gathering reel therefor, of an electric motor for continuously exerting a pull on said cable in one direction and having an armature, a resistor in series therewith, a field magnet winding in shunt circuit relation to the armature and a portion of the resistor, and a bucking series field winding in series relation to said armature.

G. The combination with an electric motor for producing a unidirectional torque and having an armature, a resistor series therewith, a shunt field Winding in shunt circuit relation to the armature and a portion of the resistor, and a buckin series field winding in series relation to sai armature, of a mechanical load ada ted to act upon said motor to turn sai armature against the motor torque and to be acted upon by said motor during its normal operation, said motor and said load being adapted for relative bodil movement 7. The combination witii a source of energy, of an electric motor mounted upon a forwardly and backwardly movable body and comprising an armature, a resistor connected in series relation therewith, a shunt field winding permanently connected across the armature and a predetermined portion of said resistor and a bucking series ield winding in series relation to said armature, whereby the voltage of said source is apportioned to produce an approximately constant resultant motor torque during forward speed, of a mechanical load that is acted upon by said motor during its forward movement and acts upon said motor to produce rotative movements thereof when the motor is moved in a backward direction.

8. In combination, a commutator motor and a load, said motor exerting a unidirectional torque and said load turning said motor at full and intermediate speeds against its torque during one part of the movement and being operated by said motor at full and intermediate speeds during another part of the movement, said motor having an armature circuit comprising an armature, a series field winding and a permanently connected impedance device, a shunt field winding energized in parallel relation to said circuit, said vseries winding being in bucking relation to said shunt Winding, and a second impedance device in series relation to both the armature and shunt field circuits.

9. In combination, a commutator motor and a load, said motor exerting a unidirectional torque and said load turning said motor at full and intermediate speeds against its torque during one part of the movement and being operated by said motor at full and intermediate speeds during another part of the movement, said motor having an armature circuit comprising an armature, a series field winding and a permanently connected resistance device, a shunt. field Winding and a second resistance device in series relation to both the armature and shunt field circuits, said resistances being of such values that the motor is operablevin both directions without overheating and with a relatively high motoring torque when running at high speed in the forward direction.

10. The combination with a source of approximately constant current, of an electrical motor associated therewith, and a load turning said motor at full and intermediate speeds against its torque during one part of the movement and being operated by said motor at full and intermediate speeds during another part of the movement, said motor having an armature circuit comprising an armature and a serially connected impedance device connected across said source, a parallel circuit comprising means for producing a shunt exciting field in said motor, and means in series circuit relation to said armature for producing a bucking exciting lield in said motor.

In testimony whereof, I have hereunto subscribed my name this 9th day of June, 1923.

EVERETT ASHWORTH. 

